Conventional gas bag are formed from fabric portions which are connected to each other by means of seams which are arranged at the margins of the fabric portions. When in fabricating gas bags several fabric portions are stitched to each other at the outer side of the gas bag a protruding seam and protruding margins of fabric materialize which due to their relative hardness or stiffness may pose a risk for the occupant. This is why, usually, the seam is disposed in the interior of the gas bag. This is achieved by turning the gas bag inside out through the deployment orifice. Another possibility consists of configuring the seam flat so that it hugs the periphery of the gas bag when deployed. This solution necessitates, however, a complicated stitching technique since the stitching device needs to engage through the deployment orifice into the gas bag so that the seam can be formed at the inner side or between the outer side and the inner side of the gas bag.